Development of Porous Titania Structure with Improved Photocatalytic Activity: Response Surface Modeling and Multi-Objective Optimization.

Elvira Mahu,Corneliu Cojocaru,Valeria Harabagiu,Iuliean Asaftei,Maria Ignat,Cristina Coromelci,Petrisor Samoila

doi:10.3390/nano10050998

Elvira Mahu, Corneliu Cojocaru + Show 5 more

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https://doi.org/10.3390/nano10050998

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Abstract

Porous titania was successfully synthesized by an ultrasound-assisted sol-gel route. The synthesis process was empirically modeled and optimized using the response surface methodology (RSM). Input variables adopted for optimization dealt with the weight ratio of precursors (r) and the sonication time (t), representing the used factors in the synthesis procedure. With regard to application, the synthesized TiO2 samples were tested for the photodegradation of two water-soluble organic pollutants under UV–Vis irradiation. Optimal conditions for the efficient pollutants’ photodegradation were found to involve a precursors ratio of 3 and a sonication time of 60 min. Thus, the M5 sample prepared under the founded optimal conditions yielded the maximal removal efficiencies of 98.4% and 46.3% for the photodegradation of CR dye and 2,4-D herbicide, respectively. In addition, the photodegradation kinetics revealed the pseudo first-order rate constants, showing the photodegradation of CR (k1 = 8.86 × 10−2 min−1) by M5 sample is about 1.3-fold faster than the photodegradation of 2,4-D pesticide (k2 = 6.84 × 10−2 min−1).

Highlights

In the last few decades, the problem of environmental pollution has increased in amplitude, owing to perpetual industrial progress
The synthesis of materials was planned according to the design of experiments in order to find out the relationship between factors affecting a process and the output of that process
Two variables were selected as key factors, namely: (1) r—the weight ratio of precursors, i.e., the ratio between the quantity of TTIP and the quantity of Pluronic F127; and (2) t—the sonication time employed for materials synthesis

Summary

Introduction

In the last few decades, the problem of environmental pollution has increased in amplitude, owing to perpetual industrial progress. In order to remove the water-soluble organic pollutants, various separation processes can be employed In this regard, the conventional methods for the remediation of waters, loaded with organic contaminants, deal with coagulation–flocculation [2,3] and adsorption [4,5] processes. The conventional methods for the remediation of waters, loaded with organic contaminants, deal with coagulation–flocculation [2,3] and adsorption [4,5] processes Despite these common techniques, research interest has been devoted towards exploring promising technologies able to destroy the hazardous organic compounds, rather than transferring the pollutants from one phase to another [6]. AOPs deal with homogenous catalysis and photocatalysis (Fenton, H2O2/UV, Fenton-like [7,8]), heterogeneous catalysis

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